The Soyuz is slated to dock with the space station shortly after midnight EDT (0400 GMT) on Thursday (May 17). Once aboard, the three spaceflyers will bring the orbiting complex back to its full complement of six residents. Their fellow Expedition 31 crewmembers — NASA's Don Pettit, Dutchman Andre Kuipers and cosmonaut Oleg Kononenko — have had the station to themselves since April 27.

The launch was a long time coming for Acaba, Padalka and Revin. They were supposed to lift off on March 29, but their flight was delayed for six weeks after a botched pressure test rendered their original Soyuz capsule unusable and forced a new one into service. [Photos: New Expedition 31 Mission Begins]